Question

The brown ring test for nitrates depends on:

• A. the reduction of nitrate to nitric oxide.
• B. oxidation ofnitric oxide to nitrogen dioxide.
• C. reduction of ferrous sulphate to iron.
• D. oxidizing action of sulphuric acid.

Answer 1

Answer: (A)

the reduction of nitrate to nitric oxide.

The brown ring test for nitrates depends on the reduction of nitrate to nitric oxide.

$N{O}_3{}^{-}+3F{e}^{2+}+4H^{+}\to 3F{e}^{3+}+NO+2H_{2}O$

$\left[Fe\right(H_{2}O{)}_6{]}^{2+}+NO\left[Fe\right(H_{2}O{)}_5\left(NO\right){]}^{2+}+H_{2}O$

Option (A) is correct.